The underlying categories system in e-voice does allow categories to have a  specific order, I just hadn't made this available in the categories tools as they currently are.

I will add this, so that you can explicitly reorder your categories. So for now just go ahead and create them, and assume that I'll improve it soon!

It might mean that any categories filters currently in use will require manually reordering as they'll no longer automatically appear in alphabetical order.

Thanks

Joe